JAJSIT3B March 2020 – April 2022 UCC27284
PRODUCTION DATA
In high-frequency switching power supply applications where high-current gate drivers such as the UCC27284 are used, parasitic inductances, parasitic capacitances and high-current loops can cause noise and ringing on the gate of power MOSFETs. Often external gate resistors are used to damp this ringing and noise. In some applications the gate charge, which is load on gate driver device, is significantly larger than gate driver peak output current capability. In such applications external gate resistors can limit the peak output current of the gate driver. it is recommended that there should be provision of external gate resistor whenever the layout or application permits.
Use Equation 9 to calculate the driver high-side pull-up current.
where
Use Equation 10 to calculate the driver high-side sink current.
where
Use Equation 11 to calculate the driver low-side source current.
where
Use Equation 12 to calculate the driver low-side sink current.
where
Both high and low-side channels of the gate driver have a peak current rating of ±3 A. These equations help reduce the peak current if needed. To establish different rise time value compared to fall time value, external gate resistor can be anti-paralleled with diode-resistor combination as shown in Section 8.2. Generally selecting an optimal value or configuration of external gate resistor is an iterative process. For additional information on selecting external gate resistor please refer to External Gate Resistor Design Guide for Gate Drivers.